Neoprene

Neoprene is the first synthetic rubber-like product. Developed in America in the 1930s, it has some properties in common with rubberized foam, but it differs in some key ways. Neoprene is water resistant and has some properties that make it better than rubber for certain uses. It played an important role when the military needs of World War II (1939–1945) created a rubber shortage. In the twenty-first century, neoprene has become widely used in tires; scuba gear and wet suits; insulated food carriers, such as coolers and lunch bags; sleeves and carriers for electronics, such as computers; insulators for wiring; gaskets and seals; weather stripping; and linings for tanks that hold petroleum products and other similar items. More than three hundred thousand tons of neoprene are produced each year.

Background

Native inhabitants of areas where rubber trees grow knew about the existence of the syrupy fluid found inside rubber trees for centuries. European explorers who traveled the world and encountered these native communities brought rubber back to Europe. By the early 1800s, rubber was used to make items such as shoe soles and life preservers. In 1844, Charles Goodyear, while attempting to overcome rubber's tendency to become brittle in cold weather and sticky in hot weather, discovered the process of vulcanization. This way of heat-treating rubber drastically increased its popularity.

By the 1920s, the development of the automobile and the need for tires caused the demand for rubber to soar. Many researchers working with chemical companies and universities began efforts to find a man-made substitute to help meet the increasing need for more rubber. One of these researchers was Reverend Julius Nieuwland, a Roman Catholic priest and chemistry professor at Notre Dame University. He developed a form of synthetic rubber in 1923. In 1930, a corporate research team at the DuPont Company expanded on Nieuwland's work and developed neoprene.

The team, led by chemist Wallace Hume Carothers, first called the discovery DuPrene. In 1937, the name was changed to neoprene to make it clear that the substance was not a finished product but an ingredient in other products. It was several years before the American public was able to purchase items made with neoprene, however. In its early years, production of the new man-made rubber was devoted to supporting the war effort during World War II. Neoprene was used to make many components of the vehicles used by American troops, such as tires, gaskets, fan belts, and hoses, and other objects that were formerly made of rubber.

Before neoprene became widely used for consumer products, Carothers and his team had to overcome a significant problem: it had a bad smell. Neoprene originally smelled more heavily of rubber than actual rubber, and the smell was so disagreeable that people would not use it. By the 1950s, Carothers and the DuPont researchers had engineered neoprene to eliminate the smell and modified it to nearly the form known in the twenty-first century. In 2014, DuPont sold the rights to neoprene to Denka Performance Elastomer LLC, a joint venture between Denka Kagaku Kogyo K.K. and Mitsui & Co. Ltd.

Overview

Neoprene is a spongy form of synthetic rubber. made by polymerizing chloroprene. Chloroprene is a colorless liquid organic compound known as a monomer. Polymerization is the process by which a chemical reaction turns monomers into long chains of molecules. The new substance, known as polychloroprene, is vulcanized. Vulcanization is the heat treatment that Goodyear used to eliminate some of the shortcomings of rubber in the 1840s. Named after Vulcan, the Roman god of fire, vulcanization increases the links between the molecules in the neoprene, making it possible for some of the properties of neoprene to be controlled to better suit the product in which it will be used. The final result is a soft, flexible form of synthetic rubber with a foam-like texture that can be formed into long sheets and can be cut and shaped into many objects. It also can be formed by molding it into the desired shape.

Neoprene is more resistant to the effects of water, oil, and chemicals than rubber. Thanks to vulcanization, elements such as its elasticity and strength can be modified, making it more useful than rubber in some cases. For instance, neoprene's stretchiness means that it can be used to make form-fitting garments, such as wet suits, and can be made to form custom covers for many types of equipment.

Neoprene's spongy composition means that it floats. Because of its sponginess, it can be used to form a protective cushion around items such as sensitive electronic equipment and to make protective athletic and medical equipment. The tiny bubbles contained in neoprene help make it an excellent insulator for either heat or cold.

Neoprene is resistant to extremes of temperature ranging from –58 degrees Fahrenheit (–50 degrees Celsius) to 248 degrees Fahrenheit (120 degrees Celsius). Some forms of neoprene are fire-resistant, making it suitable for uses in a wide range of environments and weather conditions.

Unlike rubber, neoprene is latex-free, so it is safe for those with latex allergies. This is another reason why it is a good choice for medical braces for joints and protective athletic pads. It is also resistant to abrasions and tears.

Neoprene does have some shortcomings, however. It is relatively expensive. For some uses, other products can produce better results than neoprene at a better price. It is more susceptible than rubber to the effects of certain chemicals, such as some hydrocarbons and strong oxidizing acids. Neoprene is a soft, flexible substance, so when a more rigid and durable material is needed, polyurethane is used instead.

Despite its limitations, neoprene is used to manufacture a wide range of products. These include many automotive parts; gloves, waders, and other specialized sporting and weather-resistant garments; and hoses, pipes, and other devices used to convey liquids, including chemicals. It may be used to insulate wiring on rockets or as a simple liner inside a shoe. Neoprene continues to be an important substitute for rubber, which, as a natural product, is less sustainable.

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